Bit-Tech published a review of the Scythe Ninja Copper heatsink.

The key problem for the Ninja Copper lies in the fact that we've already tested ultra low noise coolers like the Noctua NH U12P and ThermalRight Ultra 120 eXtreme, and not only were they very quiet, but both performed brilliantly thermally. When you consider that the Ninja Copper is priced in the same region as these top performers, it becomes impossible to recommend as even a silent cooling solution.

The enormously frustrating mounting process for S775 and the fingerprint magnet copper surface are the final shuriken to the heart of the Ninja Copper. Scythe has left the Ninja's design fundamentally unchanged for over three years now, while its competitors have been releasing more and more advanced coolers, packing in more cooling fins and more efficient heat pipes - this is starting to show now.

While it might be silent, we simply cannot excuse the poor thermal performance and S775 mounting problems of the Ninja Copper, and at over £40, it represents very poor value for money compared to modern competition. Silent? Yes. Deadly? Definitely not.

Scythe Ninja Copper heatsink Review